View Single Post
Old 08/22/2015, 08:52 PM   #1591
34cygni
Registered Member
 
Join Date: Mar 2013
Posts: 59
Quote:
Originally Posted by Quiet_Ivy
-People adding copepods are probably doing the right thing. They are the most efficient predator on dinos.
And you can't argue with success. But rather than culturing and dosing pods, in the long run wouldn't it be easier to build the capacity for generating pods into our systems? If biodiversity is the fix for dinos, we should be considering how to make our systems naturally more biodiverse, and since biodiversity is known to correlate with habitat diversity... Fuges, cryptic zones, Shimek-compliant RDSBs, even waterfall algae scrubbers are pod generators -- we have multiple ways to do this and at least one should be probably be incorporated into any system.

And corals eat pods, so this looks killing two really big, colorful birds with one stone.


Quote:
Originally Posted by Quiet_Ivy
-Most (if not all) dinos are actually mixotrophic and can probably switch modes under stress like the aquarist turning the lights off
Yes, this is something I avoided bringing up for fear of making my posts even longer. Scientists used to think some dinos were hetetrotrophs, some were mixos, and some were autos, but literally dozens of species believed to be autotrophs have been shown to be mixotrophic in the last 20 years, and now the consensus is that there's probably no such thing as an obligate photoautotrophic dinoflagellate, though of course it's a big ocean and one may yet turn up. And some hobbyists have reported success with blackouts -- it doesn't work with ostis, but other species may be more dependent on the autotrophic part of their metabolisms than they are -- so I didn't want to open that can of worms.

A lot of heterotrophic dinos have shown the ability to acquire plastids (the organelles in a cell where photosynthesis happens) from several different kinds of algae. But it's incorrect to say that all dinos are mixotrophic because of this -- heterotrophic species that evolved from mixotrophic dinos are known to be biologically unusual because they've jettisoned their plastids entirely (though as noted, they sometimes steal new ones from their prey). AFAIK, no other organism is known to have done this. Instead, the normal evolutionary path is for ex-mixotrophs to retain the tiny, withered, sometimes very difficult to identify remains of their plastids because they've been repurposed to serve some other biological function.

In any case, heterotrophic dinos that have acquired plastids are not truly mixotrophic. They're using the plastids to generate sugar to feed their still fully heterotropic metabolisms. As you said, they can switch modes under stress -- when food is scarce, acquiring plastids would be a logical survival strategy for a heterotrophic dino. When food is plentiful, they can eject or digest the plastids to save themselves the metabolic cost of maintaining them.


Quote:
Originally Posted by Quiet_Ivy
-Ostreopsis cysts can survive for 6 months! That is worse than ich
Glad you reported that and not me... I didn't want to be responsible for putting the idea out there that once you're past the six month mark, you're done with ostis. It's too good to be true.

That O. ovata doesn't make resting cysts capable of hatching and triggering a bloom years later seems like wishful thinking. Maybe it's true -- I hope so! -- but I wouldn't want to wager on it.


Quote:
Originally Posted by Quiet_Ivy
-Different species of dinos may occupy different ecological niches, so interventions may be targeting the wrong thing
Dinos have three known strategies for eating stuff: some of them ingest food, which limits their diet to stuff small enough to fit in their "mouths"; some of them have a sort of membrane that they exude and use to engulf prey larger than themselves, trapping prey organisms inside what amounts to an external stomach that fills up with digestive enzymes and dissolves them; and some of them jab a feeding tube into their prey and suck out their insides (some of these dinos are parasitic and can even attach themselves to fish).


Quote:
Originally Posted by Quiet_Ivy
-Many dinos feed on heterotrophic bacteria. (and cyano) But they also mention bacterial predation on dinos, especially Ostr cysts.
Pods eat dinos, but we need bacteria to eat their cysts -- perhaps that's the key to Montireef's and cal_stir's success stories. Phyto feeds pods, pods eat dinos; the dirty method (or skimmate dosing) feeds bacteria, bacteria eat dino cysts. That looks like an effective biological control strategy to me!

The risk of losing their cysts is doubtless another reason ostis use their toxins to prevent the growth of unwanted bacteria. I would wager that their preferred food bacteria rarely, if ever, attack their cysts, at least not while they're protected by a coat of mucilage.


Quote:
Originally Posted by cal_stir
After about 8 months, totally discouraged thinking I can't even give my livestock away with contaminating someone else system I stood over my sump in the next room with a bottle of bleach and contemplated getting out of the hobby for good.
I'm glad that I didn't do it
Dude -- I suspect the entire hobby is glad you didn't do it. They just don't know it yet.


34cygni is offline   Reply With Quote